DOCSLIB.ORG

Moisture in the Atmosphere

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Moisture in the Atmosphere Moisture in the Atmosphere GEOG/ENST 2331 – Lecture 9 Ahrens: Chapter 4 Last lecture ! "Atmospheric mechanics ! " PGF, gravity, Coriolis effect, friction ! "Geostrophic winds ! "Cyclones and anticyclones Moisture in the Atmosphere ! "Hydrologic cycle ! " Changes of phase ! "Humidity ! "Adiabatic processes ! "Humidity and comfort Hydrologic Cycle Ahrens: Figure 5.1 Phases of water Ahrens: Fig. 4.3 Changes of phase ! " Evaporation ! " Liquid molecules break free to become gaseous ! " Surrounding material becomes cooler ! " Condensation ! " Gaseous molecules pull together to form a liquid ! " Surrounding material becomes warmer Saturation and equilibrium •" Water exposed to a gas (or vacuum) will evaporate into it •" Water vapour will bond together and condense •" Saturation is the point at which the evaporation and condensation rates are equal A&B: Figure 5-2 More changes of phase ! " Freezing ! " Melting ! " Sublimation ! " Solid to gas ! " Deposition ! " Gas to solid ! " Sometimes also called sublimation Ahrens: Fig. 2.3 Lecture outline ! " Hydrologic cycle ! " Humidity ! " Absolute and specific humidities ! " Vapour pressure ! " Saturation ! " Dew point temperature ! " Adiabatic processes ! " Humidity and comfort Water vapour indices ! " Absolute Humidity ! " Indicates the density of water vapor expressed as a concentration (typically g/m3) ! " Specific Humidity ! " Represents a given mass of water vapor per mass of air as a ratio (typically g/kg) ! " Vapour pressure ! " The amount of pressure exerted by water molecules in the air (typically mb or hPa) ! " Also called the partial pressure of water vapour Saturation vapour pressure ! " Water vapor pressure at equilibrium ! " Dependent on temperature and pressure ! " Increases non-linearly with temperature ! " Similar to saturation specific humidity Ahrens: Active Fig. 4.10 Relative Humidity ! "Indicates the amount of water vapour in the air relative to the saturation point Vapour pressure RH = Saturation vapour pressure Specific humidity = Saturation specific humidity ! "Dependent on specific humidity, temperature, and pressure Ahrens: Active Fig. 4.11 Dew point temperature ! " Another index of moisture (not temperature) ! " Temperature at which the vapour pressure would equal the saturation vapour pressure ! " High vapour pressure means high dew point ! " If the air cools to this temperature, it will become saturated ! " If T = Td then RH = 100% Dew Point Temperature A&B: Figure 5-9 Methods of Achieving Saturation ! "Cool the air to the dew point ! "Add water vapour to the air ! "Mix cold air with warm air ! " If the warm air has higher specific humidity Achieving saturation A&B: Figure 5-9 Dew ! "At night the ground cools quickly ! " Emission of IR ! "Air above the ground cools due to conduction ! " Reaches dew point temperature ! " Condensation begins Frost ! " Like dew, but with a dew point temperature below 0°C (frost point temperature) ! " Deposition into ice crystals rather than condensation ! " Frozen dew: dew point is above 0°C, but temperature drops below after condensation Lecture outline ! "Hydrologic cycle ! "Humidity ! "Adiabatic processes ! " Dry adiabatic cooling ! "Humidity and comfort Temperature change ! "Diabatic process: adds or removes energy from a system ! " Heat transfers ! "Adiabatic process: changes temperature without adding or removing heat Diabatic processes ! "Mixing ! "Advection ! " Warm, moist air moves over a cool surface ! "Radiation ! " Night-time cooling Adiabatic processes ! " Changes in pressure cause changes in temperature ! " If the pressure drops, a parcel of air will expand and cool down ! " If the pressure rises, a parcel of air will be compressed and warm up What is a ‘parcel’ of air? ! "A volume of air with distinct properties ! "No fixed dimensions or shape ! "Creates a mental picture for visualizing atmospheric conditions ! "I talk about a cubic metre of air on occasion – a blob of air Dry adiabatic cooling Parcels expand and cool at the dry adiabatic lapse rate of 1oC/100 m (10°C/km) A&B: Figure 5-15 Adiabatic warming Descending air warms at exactly the same rate Ahrens: Figure 6.2 Lecture outline ! "Hydrologic cycle ! "Humidity ! "Adiabatic processes ! "Humidity and comfort ! " Humidex It is not the heat, it is... the Humidity ! "‘Dry heat’ ! " Sweat evaporates readily ! " Body cools down easily ! "High humidity ! " Sweat does not evaporate ! " Body cannot shed heat Even when it is cold? ! "‘Dry cold’ ! " Sweat evaporates readily ! " But the body does not sweat much ! "High humidity ! " Sweat condenses in clothing ! " Damp clothing provides much less insulation Humidex Ahrens: Fig. 4.19 Summary ! "Three important humidity indices: ! " Vapour pressure, relative humidity, dew point temperature ! "Adiabatic processes ! " Rising air expands and cools ! " Sinking air is compressed and warms ! "Humidex ! " Interesting but not so important Coming up ! "Atmospheric stability ! "Saturated lapse rates ! "Ahrens: Chapter 6 .
Load more

Recommended publications
  • Climate Variability and Heat Stress Index Have Increasing Potential Ill-Health and Environmental Impacts in the East London, South Africa
    International Journal of Applied Engineering Research ISSN 0973-4562 Volume 12, Number 17 (2017) pp. 6910-6918 © Research India Publications. http://www.ripublication.com Climate Variability and Heat Stress Index have Increasing Potential Ill-health and Environmental Impacts in the East London, South Africa Orimoloye Israel Ropo*, Mazinyo Sonwabo Perez, Nel Werner and Iortyom Enoch T. Department of Geography and Environmental Science, University of Fort Hare, Private Bag X1314, Alice, 5700, Eastern Cape Province, South Africa. *Corresponding author *Orcid ID: 0000-0001-5058-2799 Abstract activities and recent development in the region [3]. Furthermore, an investigation of extreme heat since 2003 in Impacts identified with climate variability and heat stress are Europe demonstrates that a considerable lot of the extremes already obvious in various degrees and expected to be recorded during this occasion are at least double as likely in the disruptive in the near future across the globe. Heat Index 1950s [4, 5]. In North America, there is the expected increment describes the joint impact of temperature and humidity on the in the number of hot days over the region [6]. Moreover, some human body. Therefore, we investigated the trend of relative African nations including South Africa likewise experience the humidity, temperature, heat index, and humidex and their ill effects of the outcomes of climate inconstancy in relation to likelihood impacts on human health in the East London over 3 heat-related threats [7, 8]. decades. Real-time data for daily average maximum temperature and relative humidity between 8:00 GMT and It is well known that the discomfort that occurs in warm 18:00GMT hour for the period of 1986-2016 were retrieved weather depends on the significant degree of temperature and from the South Africa Weather Service and analyzed using the humidity present in the air.
    [Show full text]
  • Installation & Owner's Manual
    Sept 2019 Humidex DVS Rev. 1.2En Installation & Owner’s Manual English This Manual Covers the Following Models DVS-CS → Crawl Space DVS-HW → Pony Wall DVS-BS → Basement DVS-CH → Heavy Duty Crawl Space DVS-BH → Heavy Duty Basement Manufactured by: ClairiTech Innovations Inc. 1095 Ohio Rd. Boudreau-Ouest, NB Canada E4P 6N4 Humidex Table of Contents Table of Contents ...................................................................................................................... 1 Service and Warranty ................................................................................................................. 2 FOR CUSTOMER ASSISTANCE ........................................................................................................................ 2 CONSUMER LIMITED WARRANTY ................................................................................................................ 3 Pre-Installation .......................................................................................................................... 4 INCLUDED COMPONENTS ............................................................................................................................. 4 TOOLS REQUIRED FOR INSTALLATION ....................................................................................................... 4 KEY INSTALLATION FACTS ........................................................................................................................... 4 IMPORTANT – WHAT NOT TO DO .........................................................................................................
    [Show full text]
  • Epidemiologic Study of Mortality During the Summer of 2003 in Italy
    P 1.8 EPIDEMIOLOGIC STUDY OF MORTALITY DURING THE SUMMER OF 2003 IN ITALY Susanna Conti *,Paola Meli *, Giada Minelli *, Renata So limini * Virgilia Toccaceli *, Monica Vichi *, M. Carmen Beltrano °° , Luigi Perini ° *National Centre of Epidemiology - Italian High er Institute for Health, Rome, Italy (°) Ufficio Centrale di Ecologia Agraria, Roma – Italy 1. INTRODUCTION the temperature (and humidity) are high and Italy is characterized by Mediterranean climate: persistent also during the night, compared with this sort of climate is usually defined temperate. those living in suburban and rural areas (“urban Seasons are clearly drawn: winter is generally heat island effect”). Heat-wave maximum effects moderate cold, spring is rainy with sunny days, essentially regard old people: there is an increase summer is warm and dry, autumn is almost of their mortality percentage because they have a cloudless, quite rainy, but never severe. During the reduced ability to thermo-regulate body temperature summer there are scarce or null rainfall and and their sweating threshold is generally more temperatures are not usually higher than 35°C. elevated than younger people; moreover, they are Rarely there are meteorological extreme events and affected by other risk-factors linked to the high generally they regard limited areas. frequency of disability, disease, and loneliness. Heat-waves can be defined as extreme and exceptional events, but it has been observed that in the last decades they became more frequent in 2. MATERIALS AND METHODS different parts
    [Show full text]
  • How Hot Is It? Reprinted with Permission from IST-Aim
    A F C I n t e r n a t i o n a l , I n c . G a s D e t e c ti o n & Air M o nitori n g S p e ci a lists How Hot Is It? Reprinted with permission from IST-Aim Mankind has often been concerned with sultriness of his environment. For some this is a mere curiosity or a comfort factor. For others it can be life threatening. In order to determine the actual degree of sultriness in a quantifiable manner several temperature indexes have been developed. Perhaps the most common one is "Humidex". It's technical name is "Apparent Temperature". This index measures the effects of humidity and temperature combined into one value to give a rough impression of how hot it feels or the sultriness. This index does have short- comings, in that it does not include the effect of wind. The little known "Corrected Effective Temperature Index" included a wind speed factor. There is another index, which incudes the effects of humidity, air speed, air temperature and the radi- ant heating factor (from the sun). This index was developed by the U.S. Military in the 1950's and has become widely accepted across the globe for industrial temperature measurements to protect employees. It's called the "wet Bulb Globe Temperature Index". It can be measured with a 6" black sphere containing a thermometer, a naturally ventilated wet thermometer, called a Wet Bulb and a regular air temperature thermometer called a Dry Bulb. There are also instruments available which measure this temperature index directly combining the three factors and their appropriate weighting values.
    [Show full text]
  • Humidex Based Heat Response Plan
    Occupational Health Clinics for Ontario Workers Inc. Humidex Based Heat Response Plan What is it? The Humidex plan is a simplified way of protecting workers from heat stress which is based on the 2009 ACGIH Heat Stress TLV® (Threshold Limit Value®) which uses wet bulb globe temperatures (WBGT) to estimate heat strain. These WBGT’s were translated into Humidex. The ACGIH specifies an action limit and a TLV® to prevent workers’ body temperature from exceeding 38°C (38.5°C for acclimatized workers). Below the action limit (Humidex 1 for work of moderate physical activity) most workers will not experience heat stress. Between Humidex 1 and Humidex 2, general heat stress controls are to be provided. Above Humidex 2 job-specific controls are needed for acclimatized workers. For unacclimatized workers job-specific controls may also be needed to reduce heat strain below the TLV® (Humidex 2) criteria. The TLV® (Humidex 2) only applies to healthy, well-hydrated, acclimatized** workers who are not on medication. Note: in the translation process some simplifications and assumptions have been made, therefore, the plan may not be applicable in all circumstances and/or workplaces (follow steps #1-5 to ensure the Humidex plan is appropriate for your workplace). Humidex 1 Response Humidex 2 25 – 29 supply water to workers on an “as needed” basis 32 – 35 post Heat Stress Alert notice; 30 – 33 encourage workers to drink extra water; 36 – 39 start recording hourly temperature and relative humidity post Heat Stress Warning notice; 34 – 37 notify workers
    [Show full text]
  • Guidelines on Cross-Border Exchange of Warnings
    World Meteorological Organization GUIDELINES ON CROSS-BORDER EXCHANGE OF WARNINGS PWS-9 WMO/TD No. 1179 Authors: Jim Davidson (Australia), Hilda Lam and CY Lam (Hong Kong, China), Stewart Wass (UK), Charles Dupuy and Federic Chavaux (France) Edited by: Haleh Kootval Cover: Rafiek El Shanawani Cover photograph: Météo-France, meteorological vigilance map © 2003, World Meteorological Organization WMO/TD No. 1179 NOTE The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of any of the participating agencies concerning the legal status of any country, territory, city or area, or of its authorities, or concern- ing the delimitation of its frontiers or boundaries. CONTENTS Page CHAPTER 1 – INTRODUCTION . 1 CHAPTER 2 – GENERAL PRINCIPLES . 2 2.1 Media as a Driving Force . 2 2.2 Focus on Public Safety . 2 2.3 Flexible Threshold Criteria . 2 2.4 Scope of Cooperation . 2 CHAPTER 3 – EXAMPLES OF CROSS-BORDER EXCHANGE OF WARNINGS . 3 3.1 Austria . 3 3.2 China – the Pearl River Estuary . 3 3.2.1 Background . 3 3.2.2 Warnings in Hong Kong . 3 3.2.3 Warnings in Macao and Guangzhou . 3 3.2.4 Coordination and Consultation . 3 3.2.5 Enhanced Data Exchange . 4 3.2.6 Annual Technical Conferences . 5 3.3 Nordic Countries . 5 3.4 Cross-border Exchanges between Germany, France and the Czech Republic . .5 3.5 The European Multi-purpose Awareness (EMMA) Programme . 6 3.5.1 Background . 6 3.5.2 The EMMA Programme . 6 3.5.3 Preconditions and Formal Arrangements .
    [Show full text]
  • Installation & Owner's Manual
    September 2019 Humidex HCS Rev. 2.1 En Installation & Owner’s Manual English This Manual Covers the Following Models HCS-APT-HDEX HCS-APTHC-HDEX Manufactured by: ClairiTech Innovations Inc. 1095 Ohio Rd. Boudreau-Ouest, NB Canada E4P 6N4 Humidex Table of Contents Table of Contents ...................................................................................................................... 1 Service and Warranty ................................................................................................................. 2 FOR CUSTOMER ASSISTANCE ........................................................................................................................ 2 CONSUMER LIMITED WARRANTY ................................................................................................................ 3 PRE-INSTALLATION ....................................................................................................................................... 4 INCLUDED COMPONENTS ............................................................................................................................. 4 TOOLS REQUIRED FOR INSTALLATION ....................................................................................................... 4 KEY INSTALLATION FACTS ........................................................................................................................... 4 IMPORTANT – WHAT NOT TO DO .......................................................................................................... 4 COMBUSTION
    [Show full text]
  • An Evaluation of Summer Discomfort in Niš (Serbia) Using Humidex
    www.gi.sanu.ac.rs, www.doiserbia.nb.rs J. Geogr. Inst. Cvijic. 2019, 69(2), pp. 109–122 Original scientific paper UDC: 911.2:551.586(497.11) https://doi.org/10.2298/IJGI1902109L Received: March 12, 2019 Reviewed: June 12, 2019 Accepted: July 5, 2019 AN EVALUATION OF SUMMER DISCOMFORT IN NIŠ (SERBIA) USING HUMIDEX Milica Lukić1*, Milica Pecelj2,3,4, Branko Protić1, Dejan Filipović1 1University of Belgrade, Faculty of Geography, Belgrade, Serbia; e-mails: [email protected], [email protected], [email protected] 2 Geographical Institute “Jovan Cvijić” SASA, Belgrade, Serbia; e-mail: [email protected] 3University of East Sarajevo, Faculty of Philosophy, Department of Geography, East Sarajevo, Republic of Srpska, Bosnia and Herzegovina 4South Ural State University, Institute of Sports, Tourism and Service, Chelyabinsk, Russia Abstract: The bioclimatic analysis of the central area of the city of Niš conducted in this paper is based on the use of the bioclimatic index Humidex, which represents subjective outdoor temperature that one feels in warm and humid environment. The purpose of this research is to observe the index change on a daily basis during the hottest part of the year (June, July, and August) over the period from 1998 to 2017. For the purposes of this analysis, hourly (7:00, 14:00), maximum and mean daily values of meteorological parameters (air temperature and relative humidity) were used, for the period of 20 years (1998–2017), which were measured at Niš weather station (43°19'N, 21°53'E, at an altitude of 202 meters). The findings indicate a gradual change in the bioclimatic characteristics of this area during this period, especially over the last decade.
    [Show full text]
  • Installation & Owner's Manual
    September 2019 Humidex HCV Rev. 4.4 En Installation & Owner’s Manual English This Manual Covers the Following Models HCV-APT-HDEX HCV-APTHC-HDEX Manufactured by: ClairiTech Innovations Inc. 1095 Ohio Rd. Boudreau-Ouest, NB Canada E4P 6N4 Humidex Table of Contents Table of Contents ...................................................................................................................... 1 Service and Warranty ................................................................................................................. 3 FOR CUSTOMER ASSISTANCE ........................................................................................................................ 3 CONSUMER LIMITED WARRANTY ................................................................................................................ 4 PRE-INSTALLATION ....................................................................................................................................... 5 INCLUDED COMPONENTS ............................................................................................................................. 5 TOOLS REQUIRED FOR INSTALLATION ....................................................................................................... 5 KEY INSTALLATION FACTS ........................................................................................................................... 5 IMPORTANT – WHAT NOT TO DO .......................................................................................................... 5 COMBUSTION
    [Show full text]
  • Installation & Owner's Manual
    April 2019 Humidex HCS myHome Rev 2.1 En Installation & Owner’s Manual English This Manual Covers the Following Models (Basement) HCS-BS-HDEX myHome (Crawl Space) HCS-CS-HDEX myHome (BoosterFan) HCS-BSF-HDEX myHome (Apartment/Slab) HCS-APT-HDEX myHome HCS-APTHC-HDEX myHome (Hard Connect) Manufactured by: ClairiTech Innovations Inc. 1095 Ohio Rd. Boudreau-Ouest, NB Canada E4P 6N4 READ AND SAVE THESE INSTRUCTIONS Humidex Table of Contents Table of Contents ...................................................................................................................... 1 Introduction ............................................................................................................................... 3 COMBUSTION APPLIANCE PRESENT IN DWELLING .................................................................................. 3 Service and Warranty ................................................................................................................. 4 FOR CUSTOMER ASSISTANCE ........................................................................................................................ 4 CONSUMER LIMITED WARRANTY ................................................................................................................ 5 PRE-INSTALLATION........................................................................................................................................ 6 INCLUDED COMPONENTS ............................................................................................................................
    [Show full text]
  • The Population Health Impacts of Heat Key Learnings from the Victorian Heat Health Information Surveillance System 2011–2013
    The population health impacts of heat Key learnings from the Victorian Heat Health Information Surveillance System 2011–2013 The population health impacts of heat Key learnings from the Victorian Heat Health Information Surveillance System 2011–2013 i To receive this publication in an accessible format phone (03) 9096 000, using the National Relay Service 13 36 77 if required. Authorised and published by the Victorian Government, 1 Treasury Place, Melbourne. © State of Victoria, June, 2015. This work is licensed under a Creative Commons Attribution 4.0 licence (creativecommons.org/licenses/by/4.0). You are free to re-use the work under that licence, on the condition that you credit the State of Victoria as author, indicate if changes were made and comply with the other licence terms. The licence does not apply to any branding including the Victorian Government logo, images or artistic works. Except where otherwise indicated, the images in this publication show models and illustrative settings only, and do not necessarily depict actual services, facilities or recipients of services. This publication may contain images of deceased Aboriginal and Torres Strait Islander peoples. Where the term ‘Aboriginal’ is used it refers to both Aboriginal and Torres Strait Islander people. Indigenous is retained when it is part of the title of a report, program or quotation. ISBN/ISSN 978-0-7311-6740-1 (pdf) Available at www.health.vic.gov.au/healthstatus (1506001) ii Contents List of tables iv List of figures iv Acknowledgements iv Summary 1 Introduction
    [Show full text]
  • Local Warming. 5 5 Average Daily Temperature Minus Seasonal Cycle and Solar Cycle at Mcguire AFB
    LOCAL WARMING ROBERT J. VANDERBEI ∗ Abstract. Using 55 years of daily average temperatures from a local weather station, I made a least-absolute-deviations (LAD) regression model that accounts for three effects: seasonal variations, the 11-year solar cycle, and a linear trend. The model was formulated as a linear programming problem and solved using widely available optimization software. The solution indicates that tem- peratures have gone up by about 2◦F over the 55 years covered by the data. It also correctly identifies the known phase of the solar cycle; i.e., the date of the last solar minimum. It turns out that the maximum slope of the solar cycle sinusoid in the regression model is about the same size as the slope produced by the linear trend. The fact that the solar cycle was correctly extracted by the model is a strong indicator that effects of this size, in particular the slope of the linear trend, can be accurately determined from the 55 years of data analyzed. The main purpose for doing this analysis is to demonstrate that it is easy to find and analyze archived temperature data for oneself. In particular, this problem makes a good class project for upper-level undergraduate courses in optimization or in statistics. It is worth noting that a similar least-squares model failed to characterize the solar cycle correctly and hence even though it too indicates that temperatures have been rising locally, one can be less confident in this result. The paper ends with a section presenting similar results from a few thousand sites distributed world-wide, some results from a modification of the model that includes both temperature and humidity, as well as a number of suggestions for future work and/or ideas for enhancements that could be used as classroom projects.
    [Show full text]